Carbon tetrabromide → 2-(Bromomethyl)[1,2,4]triazolo[1,5-a]pyridine

To a brown suspension of [1,2,4]triazolo[1,5-a]pyridin-2-ylmethanol (870 mg, 5.83 mmol) and triphenylphosphine polymer bound (2.94 g, 8.75 mmol) in dichloromethane (18 mL) was slowly added carbon tetrabromide (2.9 g, 8.75 mmol) at 0-5° C. The ice bath was removed after 5 min and the reaction mixture was stirred at RT overnight. The solvent was evaporated, the brown residue was suspended in ethyl acetate (100 mL) and the organic phase was washed with water (3×50 mL) and brine (1×50 mL). The aqueous layers were back-extracted with ethyl acetate (1×100 mL) and the combined organic layer was dried over MgSO4 and concentrated in vacuo to give the product as colorless waxy solid (1.35 g with 90% purity, 5.7 mmol, 98.2%) which was used without further purification for the next step.